The first of several former Obama administration officials and former aides to Hillary Clinton is set to be deposed Thursday after a judge ruled in January that they must answer questions under oath about the 2012 Benghazi terror attacks and the Clinton email scandal.

U.S. District Court Judge Royce Lamberth ordered the discovery after a lawsuit was brought by conservative watchdog Judicial Watch, which is seeking to uncover “whether the Benghazi scandal was one reason for keeping Mrs. Clinton’s email secret.”